Production of polyurethane foam

1. A rigid polyurethane foam comprising at least one isocyanate component, a polyol component, a catalyst which catalyzes the formation of a urethane or isocyanurate bond, and a blowing agent,

wherein the rigid polyurethane foam further comprises at least one OH-functional compound (OHC) from the partial or complete hydrogenation of ketone-aldehyde resins in the amount of by mass of at least 35 parts (pphp) based on 100 parts (pphp) of the polyol component, wherein this OH-functional compound contains at least one structural element of the formula (1 a) and of the formulae (1b) and/or (1c),

with

R is aromatic hydrocarbyl radical having 6-14 carbon atoms or (cyclo)aliphatic hydrocarbyl radical having 1-12 carbon atoms, where the hydrocarbyl radicals may be substituted,

R 1 is H, or CH 2 OH,

R 2 is H, or a radical of the formula —(CH 2 —CH(R′)O—) y —H,

wherein R′ is hydrogen, methyl, ethyl or phenyl and y=1 to 50,

k is from 2 to 15,

m is from 0 to 13,

1 is from 0 to 2,

where the sum of k+1+m is from 5 to 15, and k >m,

wherein at least 90 parts by weight of the polyols present have an OH number of greater than 100, based on 100 parts by weight of polyol components.

2. The rigid polyurethane foam according to claim 1 , wherein the OH-functional compound (OHC) is present in a total proportion by mass of 40 parts, based on 100 parts polyol component, and wherein at least 90 parts by weight of the polyols present have an OH number of greater than 150, based on 100 parts by weight of polyol components.

3. The rigid polyurethane foam according to claim 1 , wherein the OH-functional compound (OHC) is present in a total proportion by mass of from 30 to 9040 parts, based on 100 parts polyol component, and wherein at least 90 parts by weight of the polyols present have an OH number of greater than 200, based on 100 parts by weight of polyol components.

4. The rigid polyurethane foam according to claim 1 , wherein polyester polyols are present.

5. A process for producing a rigid polyurethane foam by reacting one or more polyol components with one or more isocyanate components, wherein the reaction is effected in the presence of at least one OH-functional compound (OHC) obtained by the partial or full hydrogenation of ketone-aldehyde resins in the amount of by mass of 35 parts (pphp) based on 100 parts (pphp) of the polyol component, where this OH—functional compound contains at least one structural element of the formula (1a) and of the formulae (1b) and/or (1c)

wherein

R is aromatic hydrocarbyl radical having 6-14 carbon atoms or (cyclo)aliphatic hydrocarbyl radical having 1-12 carbon atoms,

R 1 is H, or CH 2 OH,

R 2 is H, or a radical of the formula —(CH 2 —CH(R′)O—) y —H,

wherein R′ is hydrogen, methyl, ethyl or phenyl and y=1 to 50,

k is from 2 to 15,

m is from 0 to 13,

1 is from 0 to 2,

wherein the sum of k+1+m is from 5 to 15, and k >m,

wherein at least 90 parts by weight of the polyols used, have an OH number of greater than 150, based on 100 parts by weight of polyol components.

6. The rigid polyurethane foam obtained by a process according to claim 5 wherein the polyurethane foam has the OH-functional compound (OHC) is present in a total proportion by mass of from 10 to 8040 parts, based on 100 parts polyol component.

7. The rigid polyurethane foam according to claim 6 , wherein the density is from 5 to 750 kg/m 3 , and wherein at least 90 parts by weight of the polyols present have an OH number of greater than 200, based on 100 parts by weight of polyol components.

8. The rigid polyurethane foam according to claim 6 , wherein the closed-cell content of the polyurethane foam is >90%, the closed-cell content being determined in accordance with DIN ISO 4590.

9. The rigid polyurethane foam according to claim 6 , wherein the density is from 5 to 750 kg/m 3 and wherein the OH-functional compound (OHC) is present in a total proportion by mass of 40 parts based on 100 parts polyol component.

10. The rigid polyurethane foam according to claim 1 , wherein k is from 3 to 12,

wherein the sum of k+1+m is from 5 to 12, and k>m, and

wherein at least 90 parts by weight of the polyols present have an OH number of greater than 150, based on 100 parts by weight of polyol components.

11. The rigid polyurethane foam according to claim 1 ,

wherein k is from 4 to 11, and

wherein at least 90 parts by weight of the polyols present have an OH number of greater than 200, based on 100 parts by weight of polyol components.

12. The rigid polyurethane foam according to claim 1 , wherein the OH-functional compound (OHC) is present in a total proportion by mass of from 35 to 80 parts, based on 100 parts polyol component.

13. The rigid polyurethane foam according to claim 1 , wherein the OH-functional compound (OHC) is present in a total proportion by mass of from 40 to 80 parts, based on 100 parts polyol component.

14. The rigid polyurethane foam according to claim 6 , wherein the density is from 5 to 350 kg/m 3 .

15. The rigid polyurethane foam according to claim 1 , wherein the closed-cell content of the rigid polyurethane foam is greater than 90%, the closed-cell content being determined in accordance with DIN ISO 4590.

16. The rigid polyurethane foam according to claim 7 , wherein the closed-cell content of the polyurethane foam is >90%, the closed-cell content being determined in accordance with DIN ISO 4590.

17. The rigid polyurethane foam according to claim 7 , wherein the polyurethane foam has a density of from 5 to 350 kg/m 3 .

18. The rigid polyurethane foam according to claim 2 , wherein the closed-cell content is greater than 90%, the closed-cell content being determined in accordance with DIN ISO 4590.